Renewable Engine Fuel And Method Of Producing Same

ABSTRACT

The present invention provides non-petroleum high-octane fuel derived from biomass sources, and a method of producing same. The method of production involves reducing the biomass feedstocks to sugars, fermenting the sugars using microorganisms or mutagens thereof to produce ethanol or acetic acid, converting the acetic acid or ethanol to acetone, and converting the acetone to mesitylene and isopentane, the major components of the renewable engine fuel. Trimerization of acetone can be carried out in the presence of a catalyst containing at least one metal selected from the group consisting of niobium, iron and manganese. The ethanol can be converted to mesitylene in a dehydration reaction in the presence of a catalyst of zinc oxide/calcium oxide, and unreacted ethanol and water separated from mesitylene by distillation. These ethanol-based, biomass-derived fuels are fully renewable, may be formulated to have a wide range of octane values and energy, and may effectively be used to replace 100 LL aviation fuel (known as AvGas), as well as high-octane, rocket, diesel, turbine engine fuels, as well as two-cycle, spark-ignited engine fuels.

REFERENCE TO RELATED APPLICATIONS

This is a continuation-in-part of International Application No. PCT/US2009/047344, filed Jun. 15, 2009, which is an International Applicationof U.S. patent application Ser. No. 12/139,428, filed Jun. 13, 2008, nowpending, itself a continuation-in-part of 11/881,565, filed Jul. 7,2007, now pending, the contents of all of which are incorporated hereinby reference.

FIELD OF THE INVENTION

The present invention relates in general to an engine fuel produced fromrenewable materials and, in particular, a non-petroleum fuel producedfrom renewable biomass materials. Several methods of producing sameutilizing various biomass feedstocks is provided, in which bioderivedfeedstocks are reduced to sugars, the sugars are converted to ethanol oracetic acid, the acetic acid or ethanol is converted to acetone, and theacetone converted to mesitylene and other hydrocarbons such asisopentane, the major components of the renewable engine fuel. Further,biomass may be converted directly to acetone via a conventional ormodified ABE process. The fuel may be formulated with a variety ofoctane ratings, depending on application within ahigh-octanereciprocating spark ignited engine, as well as two-cycle,spark-ignited engines. Further, the components of the renewable fuel canbe mixed to form jet turbine fuel and diesel fuel.

BACKGROUND OF THE INVENTION

With the end of cheap oil and the mounting peak of world oil production,it is recognized that petroleum is a non-renewable resource, and willeventually be depleted. This realization has sparked a renewed interestin the development of renewable sources for fuel. This is particularlytrue in the case of aviation fuels used in internal combustion engines,as well as for jet (aviation) fuels.

Ethanol-based fuels for internal combustion engines have been availablefor roughly five decades. The State of California originated mandatoryoxygenation of motor fuels, which includes ethanol-based fuels, partlyto decrease the wholesale cost of fuel, and to a lesser extent to reduceair pollution per gallon of gasoline consumed. A key benefit ofethanol-based fuels is that they have a slightly higher pump octanenumber than ethanol-free gasoline. This is the reason many oil companiesprovide high ethanol content premium fuels, and lower ethanol contentregular grades of gasoline. However, since ethanol-based fuels havelower energy, pollution is generally effectively increased per mile. Toaddress this issue, research into renewable fuels made from somechemical species other than ethanol has been conducted, and such fuelshave been found to exhibit significantly higher octane numbers andincreased energy per unit volume when compared to commercial fuels andethanol-based fuels.

Octane (Power)

Octane number is a measure of the effectiveness of power production. Itis a kinetic parameter, therefore difficult to predict. Oil companiescompiled volumes of experimental octane data (for most hydrocarbons) forthe Department of Defense in the 1950's. For example, 2,2,4-trimethylpentane (isooctane) has a defined octane number of 100, and n-heptanehas a defined octane number of 0, based on experimental tests. Octanenumbers are linearly interpolated and are generally hard to extrapolate,hence some predictions for mixes can be made only once pure samplevalues are determined.

Automobile gasoline is placarded at the pump as the average of researchand motor octane numbers. These average octane numbers correlate torunning a laboratory test engine (CFR) under less severe and more severeconditions, respectively, and calculating the average octane exhibitedunder these conditions. True octane numbers lie between the research andmotor octane values. Aviation fuel has a “hard” requirement of 100 motoroctane number (MON); ethanol has a MON of 96, which makes its use viableonly when mixed with other higher octane components that are capable ofincreasing the MON to at least 100. Conventional 100 octane low lead(100 LL) contains about 3 ml of tetraethyl lead per gallon.

Range (Energy)

The inherent energy contained within gasoline is directly related tomileage, not to octane number. Automobile gasoline has no energyspecification, hence no mileage specification. In contrast, aviationfuels, a common example being 100 LL, have an energy contentspecification. This translates to aircraft range and to specific fuelconsumption. In the octane examples above, i-octane and n-heptane hadvalues of 100 and 0, respectively. From an energy perspective, theycontain heat of combustion values of 7.84 and 7.86 kcal/ml,respectively, which is the reverse of what would be expected based onpower developed. Aircraft cannot compromise range due to the sensitivityof their missions. For this reason, energy content is equally importantas MON values.

The current production volume of 100 LL is approximately 850,000 gallonsper day. 100 LL has been designated by the Environmental ProtectionAgency (EPA) as the last fuel in the United States to contain tetraethyllead. This exemption will likely come to an end in the future. In theUnited States, the Federal Aviation Administration (FAA) is responsiblefor setting the technical standards for aviation fuels. Currently, theFAA uses ASTM D910 as one of the important standards for aviation fuel.In particular, this standard defines 100 LL aviation gasoline. Thus anyreplacement 100 LL will likely also need to meet ASTM D910.

Although a number of chemical compounds have been found to satisfy themotor octane number for 100 LL octane aviation fuel, they fail to meet anumber of other technical requirements for aviation fuel. This is true,for example, for isopentane, 90 MON, and sym-trimethyl benzene 136 MON.Pure isopentane fails to qualify as an aviation fuel because it does notpass the ASTM specification D909 for supercharge octane number, ASTMspecification D2700 for motor octane number, and ASTM specificationD5191 for vapor pressure.

Pure sym-trimethyl benzene (mesitylene) also fails to qualify as anaviation fuel because it does not pass ASTM specification D2386 forfreeze point, ASTM specification D5191 for vapor pressure, and ASTMspecification D86 for the 10% distillation point. Table 3 herein showsthese test results and the ASTM standard for both isopentane andsym-trimethyl benzene.

The fermentation of a biomass using microbes to produce acetone andbutanol was first discovered by Chaim Weizmann in 1916 and is describedin U.S. Pat. No. 1,315,585 and other corresponding patents throughoutthe world. This process, known as the Weizmann process, was used by bothGreat Britain and the United States in World Wars I and II to produceacetone for the production of cordite used in making smokeless powder,and also for the derived butyrate dopes, used in aircraft surfacecovering.

A method has been discovered for producing ethanol from a plant materialby (a) providing saccharophagus degradans strain 2-40, (b) growing thesaccharophagus degradans strain 2-40 in a first portion of the plantmaterial, and (c) harvesting protein from saccharophagus degradansstrain 2-40, and mixing the protein with a second portion of the plantmaterial and yeast in an aqueous mixture. This process is described inU.S. Patent Application Publication No. US 2009/0117619 A 1 (May 7,2009), the contents of which are incorporated herein by reference.

A number of methods are known for making mesitylene from acetone andinclude, for example:

liquid phase condensation of acetone in the presence of strong acids,e.g. sulfuric acid and phosphoric acid, as described in U.S. Pat. No.3,267,165 (1966);

vapor phase condensation of acetone in the presence of a tantalumcontaining catalysts, as described in U.S. Pat. No. 2,917,561 (1959);

vapor phase condensation of acetone in the presence of a catalystemploying phosphates of the metals of group IV of the periodic system ofelements, e.g. titanium, zirconium, hafnium and tin as described in U.S.Pat. No. 3,94,079 (1976);

vapor phase reaction of acetone in the presence of molecular hydrogenand a catalyst selected from alumina containing chromia and boria asdescribed in U.S. Pat. No. 3,201,485 (1965);

vapor phase reaction of acetone using catalysts containing molybdenum asdescribed in U.S. Pat. No. 3,301,912 (1967) or tungsten as described inU.S. Pat. No. 2,425,096; a vapor phase reaction of acetone over aniobium supported catalyst with high selectivity. The catalyst ispreferably made by impregnating a silica support with an ethanolicsolution of NbCl₅ or an aqueous solution of a niobium compound in orderto deposit 2% Nb by weight and by calcining the final solid at 550° C.for 18 hours at 300° C. The condensation of acetone produces mainlymesitylene (70% selectivity) at high conversion (60-80% wt) as describedin U.S. Pat. No. 5,087,781.

It is known that alkynes can be cyclotrimerized over transition metalcatalysts to form benzene derivatives (C. W. Bird in “Transition MetalIntermediates in Organic Synthesis”, New York, London: Academic Press,1967, pp. 1-29) and U.S. Pat. No. 4,006,149). It is also known in theart to dimerize acetone to form isopentane. This process involves firstdimerizing acetone to form diacetone alcohol which is then dehydrated toform mesitytl oxide. The mesityl oxide then undergoes gas phasereformation hydrogenation to form isopentane.

Although the prior art describes various methods in which acetone can betrimerized to form mesitylene in acid media, as well as various gasphase reactions in which acetone is trimerized in acidic heterogeneouscatalytic surfaces such as silica gel, there still exists the problem ofcontrolling the (1) extent of reaction (dimerization as opposed totrimerization) as well as (2) the selectivity of the reaction(minimization of unreacted side products) while maintaining (3) highthroughput.

Accordingly, an object of the present invention is to obtain a catalystin which the extent of dimerization and trimerization can be controlledwith minimization of side reactions while maintaining a high throughput.

However, there are no known prior art processes capable of producing anengine fuel directly from biomass feedstock that satisfies FAArequirements. Furthermore, there are no known prior an processesinvolving the use of bacterial-based fermentation of a biomass toproduce acetone, and then using gas phase reactions at elevatedtemperatures to form mesitylene and isopentane from the acetone.

Accordingly, it is an object of the present invention to provide abiomass-derived lead free renewable fuels that effectively replaceshigh-octane gasoline.

It is another object of the present invention to provide fully renewablefuels for aircraft which replaces 100 LL aviation gasoline. It is afurther object of the present invention to provide high energy renewablefuels for use in turbines and other heat engines by the samemethodology; the energy content and physical properties of the renewablecomponents being tailored to the type of engine to be fueled.

It is another object of the present invention to provide a binarymixture of components which meet the technical specifications foraviation fuel of 100 LL octane. It is another object of the presentinvention to provide a non-petroleum based aviation fuel as areplacement of 100 LL octane which meets the technical specifications ofthe Federal Aviation Administration for 100 LL octane petroleum-basedaviation fuels. It is still another object of the present invention toprovide a process for the production of a biomass-derived fuel usingbacteriological fermentation to produce of the components of a binarychemical mixture which satisfies the technical specifications for 100 LLoctane aviation fuel. It is yet another object of the present inventionto provide a process for the production of a new chemical-based 100 LLoctane aviation fuel from renewable sources.

SUMMARY OF THE INVENTION

In order to achieve the objects of the present invention, the presentinventors have arduously conducted research to develop a fully renewableengine fuel derived from various biomass feedstocks which has ahigh-octane rating and high energy content. Further, the presentinventors have performed extensive research in order to identify viableprocesses for efficiently converting biomass-derived sugars to ethanolor acetic acid to acetone via a bacterium fermentation process, thenconverting the ethanol to mesitylene in a dehydration reaction, orconverting the resulting acetic acid to acetone if need be, and thenconverting the acetone to mesitylene and isopentane, the basiccomponents of the renewable fuel.

In a first preferred embodiment, a method is provided for producingbio-mass derived high-octane fuel, comprising the steps of:

(a) fermenting a biomass with a microorganism or a mutagen thereof toproduce a mixture of metabolites comprising acetone and butanol;

(b) separating the acetone from butanol and any ethanol or othersolvents in the mixture by fractional distillation;

(c) dimerizing a portion of resultant acetone from step (b) to formisopentane;

(d) trimerizing another portion of the acetone from step (b) using acatalyst containing at least one metal selected from the groupconsisting of niobium, iron, and manganese to form mesitylene, and

(e) mixing the mesitylene with the isopentane from steps (c) and (d),whereby to form the biomass-derived high-octane fuel.

In a second preferred embodiment, there is provided in the firstpreferred embodiment a method of producing bio-mass derived high-octanefuel, wherein the microorganisms are one or more chosen from amongmoorella thermoaceticum, thermoanaerobacter kiwi, moorellathermoacetica, moorella thermoautotrophica, moorella thermoaeticum,moorella thermoautotrophicum, thermoanaerobacter thermosaccharolyticum,moorella thermoaceticum, and saccharophagus degradans, strain 2-40.

In a third preferred embodiment, there is provided in the firstpreferred embodiment a method of producing bio-mass derived high-octanefuel, wherein the biomass is selected from the group consisting ofsugars, celluloses, lignins, starches, and lignocelluloses.

In a fourth preferred embodiment, there is provided in the firstpreferred embodiment a method of producing bio-mass derived high-octanefuel, wherein the biomass is selected from the group consisting of hardwoods, grasses, corn stover, sorghum, corn fiber, and oat hulls, whichare pretreated with enzymes or strong acids to break any hemicellulosechains into their sugar monomers.

In a fifth preferred embodiment, there is provided in the firstpreferred embodiment a method of producing bio-mass derived high-octanefuel, wherein the fermentation in step (a) is conducted in an anaerobicreactor in the absence of oxygen.

In a sixth preferred embodiment, there is provided in the firstpreferred embodiment a method of producing bio-mass derived high-octanefuel, wherein metabolites of acetone, butanol and ethanol from step (a)are stripped from the mixture produced in the fermentation process instep (a) when concentrations thereof over 2 to 3 wt % are obtained,whereby to avoid any poisoning of the microorganism.

In a seventh preferred embodiment, there is provided in the firstpreferred embodiment a method of producing bio-mass derived high-octanefuel, wherein the trimerizing of acetone in step (d) is carried out inthe gas phase by passing acetone in contact with a catalyst containingniobium oxide at elevated temperatures. Preferably, this process isconducted within a temperature range of 200-600° C.

In an eighth preferred embodiment, there is provided in the firstpreferred embodiment a method of producing bio-mass derived high-octanefuel, wherein the dimerization of acetone in step (c) is carried out ina catalytic reaction to yield isopentane.

In a ninth preferred embodiment, there is provided in the firstpreferred embodiment a method of producing bio-mass derived high-octanefuel, wherein the dimerization of acetone in step (c) is carried out ina gas phase catalytic reaction.

In a tenth preferred embodiment, there is provided in the seventhpreferred embodiment above a method of producing bio-mass derivedhigh-octane fuel, wherein the trimerization of acetone in step (d) iscarried out with a catalyst of niobium oxide on a base of aluminawashcoat on calcined aluminized stainless steel corrugated film.

In an eleventh preferred embodiment, there is provided in the seventhpreferred embodiment above a method of producing biomass derivedhigh-octane fuel, wherein the trimerization of acetone in step (d) iscarried out with a catalyst of niobium oxide on a base of alumina beads.

In a twelfth preferred embodiment, there is provided in the seventhpreferred embodiment above a method of producing biomass derivedhigh-octane fuel, wherein the trimerization of acetone in step (d) iscarried out with a catalyst of niobium oxide on silica gel.

In a thirteenth preferred embodiment, there is provided in the seventhpreferred embodiment above a method of producing biomass derivedhigh-octane fuel, wherein the trimerization of acetone in step (d) iscarried out with a catalyst of manganese nitrate on alumina beads.

In a fourteenth preferred embodiment, there is provided in a seventhpreferred embodiment above a method of producing biomass derivedhigh-octane fuel, wherein the trimerization of acetone in step (d) iscarried out with a catalyst of manganese nitrate on silica gel.

In a fifteenth preferred embodiment, there is provided in the seventhpreferred embodiment above a method of producing biomass derivedhigh-octane fuel, wherein the trimerization of acetone in step (d) iscarried out with a catalyst of manganese nitrate on a base of aluminawashcoat on calcined aluminized stainless steel corrugated film.

In a sixteenth preferred embodiment, there is provided a method ofproducing biomass derived high-octane fuel, comprising the steps of

(a) fermenting a biomass with a microorganism or a mutagen thereof toproduce a mixture of metabolites comprising ethanol;

(b) carrying out a dehydration reaction of ethanol in the presence of azinc oxide catalyst on a calcium base at elevated temperatures of about350° C. and at elevated pressures; and

(c) cooling vapors from the dehydration reaction to condense water andseparate unreacted ethanol to acetone through distillation to form theresultant mesitylene.

In a seventeenth preferred embodiment, there is provided in thesixteenth preferred embodiment above a method of producing biomassderived high-octane fuel, wherein the microorganisms are one or morechosen from among moorella thermoaceticum, thermoanacrobacter kivui,moorella thermoacetica, moorella thermoautotrophica, moorellathermoacticum, moorella thermoautotrophicum, thermoanaerobacterthermosaccharolyticum, moorella thermoaceticum, and saccharophagusdegradans, strain 2-40.

In an eighteenth preferred embodiment, there is provided in thesixteenth preferred embodiment above a method of producing biomassderived high-octane fuel, wherein the biomass is selected from the groupconsisting of sugars, celluloses, lignins, starches, andlignocelluloses.

In a nineteenth preferred embodiment, there is provided in the sixteenthpreferred embodiment a method of producing biomass derived high-octanefuel, wherein ethanol is produced from a plant material comprising thesteps of:

(a) providing saccharophagus degradans, strain 2-40;

(b) growing the saccharophagus degradans, strain 2-40 in a first portionof the plant material;

(c) harvesting protein from saccharophagus degradans, strain 2-40, and

(d) mixing the protein with a second portion of the plant material andyeast in an aqueous mixture, thereby producing ethanol.

In a twentieth preferred embodiment, there is provided in the nineteenthpreferred embodiment above a method of producing biomass derivedhigh-octane fuel, wherein the aqueous mixture contains from about 1% toabout 10% salt.

In a twenty first preferred embodiment, a method of producing biomassderived high-octane fuel is provided, comprising the steps of

(a) growing saccharophagus degradans, strain 2-40, in a first portion ofplant material;

(c) harvesting protein from saccharophagus degradans, strain 2-40 fromthe first portion of plant material;

(d) mixing the protein with a second portion of the plant material andyeast in an aqueous mixture, thereby producing ethanol;

(e) converting the ethanol in whole or in part to acetone;

(f) separating the acetone from any remaining ethanol and/or otherbyproducts;

(g) dimerizing a portion of the acetone from step (f) to formisopentane;

(h) trimerizing another portion of the acetone from step (f) using acatalyst containing at least one metal and/or oxide thereof selectedfrom the group consisting of niobium, iron, and manganese to formmesitylene, and

(i) mixing the mesitylene with the isopentane from steps (c) and (d),whereby to form the biomass-derived high-octane fuel.

In a twenty second preferred embodiment, the method of producing biomassderived high-octane fuel of the twenty first embodiment above isprovided, wherein the ethanol is converted to acetone in the presence ofiron oxide catalysts.

In a twenty third preferred embodiment, the method of producing biomassderived high-octane fuel of the twenty first embodiment above isprovided, wherein the ethanol is converted to acetone in the presence ofzinc oxide-calcium oxide catalysts and water vapor.

In a twenty-fourth preferred embodiment there is provided in thetwenty-first embodiment a method of producing biomass derivedhigh-octane fuel, wherein the ethanol is converted to acetone by a gasphase catalystic reaction at elevated temperatures.

In a twenty-fifth preferred embodiment there is provided in thetwenty-first embodiment a method of producing bio-mass derivedhigh-octane fuel, wherein the trimerizing of acetone in step (h) iscarried out in the gas phase by passing acetone in contact with acatalyst containing niobium oxide at elevated temperatures.

In a twenty-sixth preferred embodiment there is provided in thetwenty-first preferred embodiment a method of producing bio-mass derivedhigh-octane fuel, wherein the dimerization of acetone in step (g) iscarried out in a catalytic reaction to yield isopentane.

In a twenty-seventh preferred embodiment there is preferred in thetwenty-first preferred embodiment a method of producing bio-mass derivedhigh-octane fuel, wherein the dimerization of acetone in step (g) iscarried out in a gas phase catalytic reaction.

In a twenty-eighth preferred embodiment there is provided in thetwenty-first preferred embodiment a method of producing bio-mass derivedhigh-octane fuel, wherein the trimerization of acetone in step (g) iscarried out with a catalyst of niobium oxide on a base of aluminawashcoat on calcined aluminized stainless steel corrugated film.

In a twenty-ninth preferred embodiment there is provided in thetwenty-first preferred embodiment a method of producing biomass derivedhigh-octane fuel, wherein the trimerization of acetone in step (g) iscarried out with a catalyst of niobium oxide on a base of alumina beads.

In a thirtieth preferred embodiment there is provided in thetwenty-first preferred embodiment a method of producing biomass derivedhigh-octane fuel, wherein the trimerization of acetone in step (g) iscarried out with a catalyst of niobium oxide on silica gel.

In a thirty-first preferred embodiment there is provided in thetwenty-first preferred embodiment a method of producing biomass derivedhigh-octane fuel, wherein the trimerization of acetone in step (g) iscarried out with a catalyst of manganese nitrate on alumina beads.

In a thirty-second preferred embodiment there is provided in thetwenty-first preferred embodiment a method of producing biomass derivedhigh-octane fuel, wherein the trimerization of acetone in step (g) iscarried out with a catalyst of manganese nitrate on silica gel.

In a thirty-third preferred embodiment there is provided in thetwenty-first preferred embodiment a method of producing biomass derivedhigh-octane fuel, wherein the trimerization of acetone in step (g) iscarried out with a catalyst of manganese nitrate on a base of aluminawashcoat on calcined aluminized stainless steel corrugated film.

In a thirty-fourth preferred embodiment there is provided in the firstpreferred embodiment a method of producing biomass derived high-octanefuel according, wherein the microorganism is clostridium or variantsthereof.

In a thirty-fifth preferred embodiment there is provided in thesixteenth preferred embodiment a method of producing biomass derivedhigh-octane fuel according, wherein the microorganism is clostridium orvariants thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph of the motor octane number (MON) as a function of wt %of mesitylene for the biomass-derived high-octane fuel of the presentinvention.

FIG. 2 is a graph of the Reid vapor pressure as a function of the wt %of mesitylene for the biomass-derived high-octane fuel of the presentinvention.

FIG. 3( a) is a process flow diagram illustrating the process ofextracting 6C (six carbon-containing) sugars from sugar biomassfeedstocks.

FIG. 3( b) is a process flow diagram illustrating the process ofextracting 6C (six carbon-containing) sugars from starch/grain biomassfeedstocks.

FIG. 3( c) is a process flow diagram illustrating the process ofextracting 6C (six carbon-containing) sugars from lignocellulosicbiomass feedstocks.

FIG. 4( a) is a process flow diagram illustrating an ethanolic processwherein 6C sugars are fermented first to ethanol, and then to aceticacid.

FIG. 4( b) is a process flow diagram illustrating an ethanolic processwherein 6C sugars are converted to ethanol.

FIG. 4( c) is a process flow diagram illustrating an acetic processwherein 5C and 6C sugars are converted to acetic acid.

FIG. 4( d) is a process flow diagram illustrating an acetic processwherein 5C and 6C sugars are fermented to produce lactic acid, andlactic acid is then fermented to acetic acid.

FIG. 5 is a process flow diagram illustrating the process wherein theacetic acid produced in the processes shown in FIGS. 4( a), 4(c) and4(d) is converted to acetone, the acetone is then converted tomesitylene and isopentane, and finally combined to produce the fuel ofthe present invention.

FIG. 6 is a process flow diagram illustrating the process wherein theethanol produced in the process shown in FIG. 4( b) is converted toacetone, the acetone is then converted to mesitylene and isopentane, andfinally combined to produce the fuel of the present invention.

FIG. 7 is a process flow diagram illustrating a process of converting 6Csugars to the fuel of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

As discussed above, the present invention provides a non-petroleum-basedrenewable fuel comprised of fully renewable components, i.e., componentsderivable from biosources. In particular, as provided in the firstembodiment herein, a bio-mass derived high-octane aviation fuel isprovided, which is comprised of (a) at least one aromatic hydrocarbon,and (b) at least one isoparaffin having from 4 to 6 carbon atoms. Thisbiomass-derived fuel has been experimentally demonstrated to have ahigh-octane rating, and is ideal for use in aviation applications. Forexample, the fuel of the present invention may be utilized as areplacement for the conventional 100 LL (low lead) aviation fuel usedthroughout the world in private aviation, as well as for use in turbine(jet) engine applications.

In a preferred embodiment, the aromatic hydrocarbon is sym-trimethylbenzene (mesitylene), also known as 1,3,5-trimethylbenzene. Variousexperimental studies were conducted to determine the effect ofmesitylene concentration on MON, and in particular the optimal weightpercent range thereof that provides the desired MON. The results ofthese tests, which applied the test standards under ASTM D2700 motoroctane number in lean configurations, are shown in FIG. 1, wherein theX-axis denotes mesitylene concentration in weight percent, and theY-axis denotes MON of the fuel.

Since the minimum motor octane number required for 100 LL octaneaviation fuel is 99.5, it can be seen from FIG. 1 that all blendsgreater than about 70 wt % mesitylene meet that specification. Inparticular, when the aromatic hydrocarbon (mesitylene) is present in anamount of from about 60-85 wt %, a MON of from 96-105 is obtained. Whenthe mesitylene constitutes 70-85 wt % of the fuel composition, the MONis observed to be 100 to 105. When the fuel contains mesitylene in anamount of 75 wt %, an MON of about 101-102 is obtained.

Further tests were carried out according to ASTM D5191 to determine theReid vapor pressure as a function of concentration (wt %) of mesitylenefor the fuel of the present invention. The 0% and 100% (pure chemicals)were not tested. The results of these tests are illustrated in FIG. 2,wherein the X-axis denotes the concentration of mesitylene in weightpercent, and the Y-axis denotes the Reid vapor pressure in psi (poundsper square inch). The Reid vapor pressure requirement of 100 LL octaneaviation fuel is between 5.5 and 7.1 psi. As illustrated in FIG. 2,mesitylene concentrations of from about 70-85 wt % meet the Reid vaporpressure requirement for 100 LL octane aviation fuel. It should be notedthat neither pure mesitylene nor pure isopentane meet thisspecification.

The isoparaffin of the above mentioned high-octane aviation fuel ispresent in the fuel in an amount of from about 15-40 wt %, morepreferably 15-30 wt %. The isoparaffin is preferably a normally liquidisoparaffin, such as isopentane.

In an alternative embodiment of the present invention, a renewable fuelin accordance with the fuel of the first embodiment discussed above isprovided, further comprising a straight chain alkane. Preferably, thestraight chain alkane is a 3 carbon alkane, i.e., propane. Further, inthis embodiment, rather than a branched chain 5 carbon alkane, such asisopentane as described above, a straight chain alkane, such as pentaneis used. Such a fuel is preferably used as an automotive fuel.

In a further alternative embodiment of the present invention, arenewable fuel in accordance with the fuel of the first embodimentdiscussed above is provided, further comprising a straight chain alkane.Preferably, the straight chain alkane is a 3 carbon alkane, i.e.,propane. Such a fuel is preferably used as a turbine engine fuel inaviation applications.

The present inventors conducted further tests according to six ASTMstandards (methods) to determine various characteristics of puremesitylene, pure isopentane, Swift 702 pure fuel according to thepresent invention (comprised of 83 wt % of mesitylene and 17 wt %isopentane) and conventional 100 LL aviation fuel. The results of thesecomparative tests are illustrated in Table 3 below:

TABLE 1 ASTM Method Test Mesitylene Isopentane Swift 702 100 spec D2700Motor 136 90.3 104.9 ≧99.5 Octane Number D909 Supercharge ON 170 92.3133.0 130.0 D5191 Vapor Pressure ≦5.5 ≧7.1 5.7 5.5 to 7.1 D2386 FreezingPt −49 −161 −63 ≦58 D86 10% Distillation Pt. 165 28 65 ≦75 D86 EndDistillation 185 28 165 ≦170 Pt.

Applicants unexpectedly discovered from these tests that addingisopentane to mesitylene in a certain concentration as called for hereinincreases the vapor pressure, lowers the freezing point, and lowers the10% distillation point of mesitylene to within the ASTM standard asshown in Table 1. Applicants also unexpectedly discovered that addingmesitylene to isopentane to form a 100 octane aviation fuel raises themotor octane number of the isopentane (as compared to pure isopentane),raises the supercharge octane number of isopentane (as compared to pureisopentane), and lowers the vapor pressure of isopentane (as compared topure isopentane) to within the ASTM D910 specification.

As mentioned above, the present inventors have further developed amethod of producing bio-mass derived high-octane aviation fuel,comprising a first step of extracting 5C and 6C sugars from the biomass,and fermenting the extracted sugars with a microorganism or mutagenthereof to produce a mixture of metabolites comprising acetone andbutanol. In particular, various processes may be utilized to ferment thesugars extracted from the biomass, as illustrated in FIGS. 3( a)-3(d).Then, as illustrated in FIGS. 4( a)-4(d), the sugars are fermented toproduce ethanol or acetic acid. This fermentation step is preferablyconducted in an anaerobic reactor in the absence of oxygen.

Various experimental tests were carried out to determine whichmicroorganisms are most capable of converting the biomass-derived sugarsto ethanol and acetic acid. The results of these tests, as well as theconditions under which these tests were carried out, are illustrated inTable 2 below.

TABLE 2 Fastest Fermentation Doubling Acetate Sugars Temperature TimeProduced Microorganism Fermented pH (° C.) (Hours) (g/L) MoorellaGlucose, 7.2 57 6 25 Thermoaceticum Xylose Thermoanaerobacter Glucose6.5 66 3 43 Kivui Moorella Glucose, 7 55 10 20 Thermoacetica Xylose,Lactic Acid Moorella Glucose, 6.5 60 10 30 Thermoautotrophica Xylose,Lactic Acid Moorella Glucose, 6.9 58 6 25 Thermoaeticum Xylose MoorellaGlucose, 6.9 56 6 35 Thermoautotrophicum Xylose ThermoanaerobacterGlucose 6.9 45 6 20 thermosaccharolyticum Morella Glucose, 6.9 60 6 90Thermoaceticum Xylose

In view of the results of the results of the tests discussed above,preferably, the microorganisms (MO's) used to carry out thisfermentation process are one or more of moorella thermoaceticum,thermoanaerobacter kivui, moorella thermoacetica, moorellathermoautotrophica, moorella thermoaeticum, moorellathermoautotrophicum, thermoanaerobacter thermosaccharolyticum, moorellathermoaceticum. saccarophagus degradans strain 2-40, more preferably,thermoanaerobacter kivui, and/or moorella thermoaceticum are utilized,as they have been experimentally shown to produce the greatest acetoneyield. However, selection of the MO's is dependent upon the particularbiomass feedstock chosen, and can include, for example, clostridium andvariants thereof.

The general classes of biomasses used as the base feedstocks in themethod of production provided herein are those from which 5C and 6Csugars may be derived, such as sugars, celluloses, lignins, starches,and lignocelluloses. Preferably, hard woods, grasses, corn stover,sorghum, corn fiber, and/or oat hulls are utilized. To increase theefficiency of the fermentation process, preferably, these feedstocks arepretreated with enzymes or strong acids to break any hemicellulosechains into their sugar monomers.

Alternatively, in a preferred embodiment, ethanol may be produced from aplant material using the bioorganism saccharophagus degradans, strain2-40. In particular, saccharophagus degradan is first grown in a firstportion of the plant material. Then, protein is harvested fromsaccharophagus degradans, strain 2-40, and mixed with a second portionof the plant material and yeast in an aqueous mixture to produceethanol.

The ethanol is then converted in whole or in part to acetone.Preferably, the ethanol is converted to acetone in the presence of ironoxide catalysts, or converted to acetone in the presence of zincoxide-calcium oxide catalysts and water vapor. In addition, preferably,the acetone is separated from any remaining ethanol and/or otherbyproducts not converted to acetone in these processes.

In a second step of the method of the present invention, the acetone isseparated from butanol, ethanol or other solvents in the metabolitemixture. In particular, the metabolites of acetone, butanol and ethanolproduced in the first step are separated from the fermentation mixturewhen concentrations thereof exceed 2 to 3 wt %. It has been unexpectedlydiscovered that that this avoids possible poisoning of the microorganismor mutagens thereof. This may be performed using any conventional priorart process. In a preferable embodiment, fractional distillation isutilized to perform this function.

In a third step, a portion of the resultant acetone produced in thesecond step is dimerized to form isopentane. Any conventional processmay be utilized to carry out this dimerization step. Preferably,however, dimerization of acetone is carried out in a catalytic reactionto yield isopentane. Most preferably, this dimerization step is carriedout in a gas phase catalytic reaction.

In a fourth step, another portion of the acetone derived in the secondstep described above is trimerized to form mesitylene. As in the thirdstep above, the trimerization process may be carried out using anyconventional trimerization process. Preferably, the trimerization ofacetone is carried out in the gas phase by reacting acetone withsulfuric or phosphoric acid at elevated temperatures. Further, thistrimerization step is preferably carried out in the presence of acatalyst.

In order to tailor the catalyst for the three control parameters above,the surface acidity is preferably controlled. Changing to a more acidicsubstrate such as silica gel or amorphous silica or a more neutralcatalyst substrate such as alumina have shown unexpected results due tosurface acidity.

The trimerization catalyst preferably contains at least one metalselected from the group consisting of Row 4 transition metals (V, Cr,Mn, Fe, Co, Ni, Cu), Row 5 transition metals (Nb, Mo, Ag), and Row 6transition metals (W), all as fully developed oxides.

Preferably, Column 2A alkaline earth metals (Mg, Ca, Sr, Ba), and Column1A alkaline metals (Na, K) as the developed oxides, are effective aspromoters or co-catalysts in the trimerization catalysts.

The catalyst of the present invention is preferably comprised of threeportions, (1) a catalyst substrate or base with a defined surfaceacidity and surface area, (2) the catalyst itself which is preferablydispersed on the substrate as a developed oxide and, optionally, (3) apromoter or co-catalyst which is preferably an alkaline species whichtailors the overall acid properties of the catalyst ensemble.

In order to tailor the catalyst for the three controlled parametersabove, the surface acidity is preferably controlled. Changing to a moreacidic catalyst substrate such as silica gel or amorphous silica or amore neutral catalyst substrate such as alumina have produced unexpectedresults due to surface acidity.

In low flow systems, it is preferred to use a catalyst in bead form.These catalysts are prepared by using a base of alumina or silicacatalyst base, in bead form, which can be soaked with a defined volumeof impregnating solution. The volume of impregnating solution is definedby the apparent bulk density (ABD) of the catalyst base. Theconcentration of the impregnating solution can be adjusted such that adefined amount of solution is in contact with the catalyst base. Forexample, 107.05 g of alumina beads are contacted with 27.83 g of ferricnitrate nonahydrate dissolved to make 100 ml of impregnating solution.The alumina beads have an ABD of 0.7146, hence the dry volume is 150 ml.The 100 ml of impregnating solution just covers the particular catalystbase. The base and the solution are left in contact for one hour. Themix is dried in a drying oven at 200° C. until at constant weight. Thedried catalyst is calcined in a calcining furnace overnight at 700° C.In this example, 3.58 g of stable iron oxide is deposited on 150 ml ofbase, which is more conveniently expressed as 675 g per cubic foot.

In high flow rate systems, monolithic catalysts is preferably used. Inthe monolithic catalyst, a defined slurry of catalyst compound is placedin contact with a continuous ribbon of a metallic substrate bonded to analumina wash coat. The slurry is dried, then calcined similar to theprocess above. The slurry concentration and temperatures for drying andcalcining are chosen to ensure the correct deposition and fixation ofthe defined oxide. The deposited catalyst is expressed in units of gramsper cubic foot similar to the method discussed above. Preferred highflow rate catalysts include manganese nitrate and niobium oxide.

Lastly, the mesitylene with the isopentane derived in the third andfourth steps described above are mixed in the appropriate proportions toform synthetic high-octane aviation fuel. Specifically, the proportionsof these components are mixed in the weight percentages described above.The process steps utilized to carry out the third through fifth steps ofthe present invention are illustrated in FIGS. 5 and 6.

An alternative overall process view is illustrated in FIG. 7. In thisalternative embodiment of the present invention, natural gas or gasproduced from biomass is converted to propane, propane is converted topropyne (methylacetylene), and propyne to mesitylene and isopentane. Itshould be noted that this reaction process is similar to the method ofmanufacture discussed above using acetone. However, no water isgenerated, and the reaction is all gas phase.

It should be recognized that the alternative embodiment fuels mentionedabove comprising, for example, pentane or propane, are manufacturedusing the above described process. However, the pentane and propanecomponents can be derived from acetone instead of, or in addition to,the mesitylene and isopentane components in a similar manner. Further,if desired, conventional fuel additives, such as surfactants, viscosityimprovers, anti-icing additives, thermal stability improver additives,and metal de-activators to suppress the catalytic effect which somemetals, particularly copper, have on fuel oxidation. However, theseadditional components must be selected with care so as to ensure thatthey have no effect on the MON, Reid vapor pressure, etc.

In another preferred embodiment mesitylene can be made in a processincluding (1) fermentation of a biomass to form ethanol, (2) adehydration reaction of ethanol to form acetone and water, (3) theseparation by distillation of unreacted ethanol from water and acetone,and (4) the gas phase reaction of acetone to form mesitylene. For thereaction step ethanol can be metered out and then vaporized. The ethanolvapor can be superheated to 350° C. at 100 psig and then the superheatedvapor is passed through a reactor containing a catalyst bed. A preferredcatalyst is zinc oxide/calcium oxide, for the ethanol to acetonereaction.

After being decompressed to atmospheric pressure, the gas is liquefiedin a condenser and collected. Preferably, a dry ice condenser liquefiesany vapors that pass through a primary condenser that are condensabledown to minus 78° C. The raw product can then be distilled, unreactedethanol (overheads) being separated from acetone and water (bottoms),and through a gas phase reaction to form mesitylene from the acetone.The ethanol (overhead stream) can be recycled to the reactor.

As long as there is no acetone present, water can be separated frommesitylene via a phase separator because of their mutual low solubility.The water (heavy phase) can then be drawn off and disposed of.Mesitylene can be sampled and stored. The condensed ethanol can berecycled back to the reactor feed tank. The condensed acetone can berecycled as well.

Although specific embodiments of the present invention have beendisclosed herein, those having ordinary skill in the art will understandthat changes can be made to the specific embodiments without departingfrom the spirit and scope of the invention. The scope of the inventionis not to be restricted, therefore, to the specific embodiments.Furthermore, it is intended that the appended claims cover any and allsuch applications, modifications, and embodiments within the scope ofthe present invention.

1. A method of producing bio-mass derived high-octane fuel, comprisingthe steps of: (a) fermenting a biomass with a microorganism or a mutagenthereof to produce a mixture of metabolites comprising acetone andbutanol; (b) separating the acetone from butanol and any ethanol orother solvents in the mixture by fractional distillation; (c) dimerizinga portion of resultant acetone from step (b) to form isopentane; (d)trimerizing another portion of the acetone from step (b) using acatalyst containing at least one metal selected from the groupconsisting of niobium, iron, and manganese to form mesitylene, and (e)mixing the mesitylene with the isopentane from steps (c) and (d),whereby to form the biomass-derived high-octane fuel.
 2. The method ofproducing bio-mass derived high-octane fuel of claim 1, wherein themicroorganisms are one or more chosen from among moorellathermoaceticum, thermoanaerobacter kivui, moorella thermoacetica,moorella thermoautotrophica, moorella thermoaeticum, moorellathermoautotrophicum, thermoanaerobacter thermosaccharolyticum, moorellathermoaceticum, and saccharophagus degradans, strain 2-40.
 3. The methodof producing bio-mass derived high-octane fuel of claim 1, wherein thebiomass is selected from the group consisting of sugars, celluloses,lignins, starches, and lignocelluloses.
 4. The method of producingbio-mass derived high-octane fuel of claim 1, wherein the biomass isselected from the group consisting of hard woods, grasses, corn stover,sorghum, corn fiber, and oat hulls, which are pretreated with enzymes orstrong acids to break any hemicellulose chains into their sugarmonomers.
 5. The method of producing bio-mass derived high-octane fuelaccording to claim 1, wherein the fermentation in step (a) is conductedin an anaerobic reactor in the absence of oxygen.
 6. The method ofproducing bio-mass derived high-octane fuel of claim 1, whereinmetabolites of acetone, butanol and ethanol from step (a) are strippedfrom the fermentation when concentrations thereof over 2 to 3 wt % areobtained, whereby to avoid any poisoning of the microorganism.
 7. Themethod of producing bio-mass derived high-octane fuel of claim 1,wherein the trimerizing of acetone in step (d) is carried out in the gasphase by passing acetone in contact with a catalyst containing niobiumoxide at elevated temperatures.
 8. The method of producing bio-massderived high-octane fuel of claim 1, wherein the dimerization of acetonein step (c) is carried out in a catalytic reaction to yield isopentane.9. The method of producing bio-mass derived high-octane fuel of claim 1,wherein the dimerization of acetone in step (c) is carried out in a gasphase catalytic reaction.
 10. The method of producing bio-mass derivedhigh-octane fuel of claim 7, wherein the trimerization of acetone instep (d) is carried out with a catalyst of niobium oxide on a base ofalumina washcoat on calcined aluminized stainless steel corrugated film.11. The method of producing biomass derived high-octane fuel of claim 7,wherein the trimerization of acetone in step (d) is carried out with acatalyst of niobium oxide on a base of alumina beads.
 12. The method ofproducing biomass derived high-octane fuel of claim 7, wherein thetrimerization of acetone in step (d) is carried out with a catalyst ofniobium oxide on silica gel.
 13. The method of producing biomass derivedhigh-octane fuel of claim 7, wherein the trimerization of acetone instep (d) is carried out with a catalyst of manganese nitrate on aluminabeads.
 14. The method of producing biomass derived high-octane fuel ofclaim 7, wherein the trimerization of acetone in step (d) is carried outwith a catalyst of manganese nitrate on silica gel.
 15. The method ofproducing biomass derived high-octane fuel of claim 7, wherein thetrimerization of acetone in step (d) is carried out with a catalyst ofmanganese nitrate on a base of alumina washcoat on calcined aluminizedstainless steel corrugated film.
 16. A method of producing biomassderived high-octane fuel, comprising the steps of: (a) fermenting abiomass with a microorganism or a mutagen thereof to produce a mixtureof metabolites comprising ethanol, (b) carrying out a dehydrationreaction of ethanol in the presence of a zinc oxide catalyst on acalcium base at elevated temperatures of about 350° C. and at elevatedpressures, and (c) cooling vapors from the dehydration reaction tocondense water and separate unreacted ethanol to acetone throughdistillation to form the resultant mesitylene.
 17. The method ofproducing biomass derived high-octane fuel, according to claim 16,wherein the microorganisms are one or more chosen from among moorellathermoaceticum, thermoanacrobacter kivui, moorella thermoacetica,moorella thermoautotrophica, moorella thermoacticum, moorellathermoautotrophicum, thermoanaerobacter thermosaccharolyticum, moorellathermoaceticum, and saccharophagus degradans, strain 2-40.
 18. Themethod of producing biomass derived high-octane fuel according to claim16, wherein the biomass is selected from the group consisting of sugars,celluloses, lignins, starches, and lignocelluloses.
 19. The method ofproducing biomass derived high-octane fuel, according to claim 16,wherein ethanol is produced from a plant material comprising the stepsof: (a) providing saccharophagus degradans, strain 2-40; (b) growing thesaccharophagus degradans, strain 2-40 in a first portion of the plantmaterial; (c) harvesting protein from saccharophagus degradans, strain2-40, and (d) mixing the protein with a second portion of the plantmaterial and yeast in an aqueous mixture, thereby producing ethanol. 20.The method of producing biomass derived high-octane fuel, according toclaim 19, wherein the aqueous mixture contains at least 1% salt and/orat most 10% salt.
 21. A method of producing biomass derived high-octanefuel is provided, comprising the steps of: (a) growing saccharophagusdegradans, strain 2-40, in a first portion of plant material; (c)harvesting protein from saccharophagus degradans, strain 2-40 from thefirst portion of plant material; (d) mixing the protein with a secondportion of the plant material and yeast in an aqueous mixture, therebyproducing ethanol; (e) converting the ethanol in whole or in part toacetone; (f) separating the acetone from any remaining ethanol and/orother byproducts; (g) dimerizing a portion of the acetone from step (f)to form isopentane; (h) trimerizing another portion of the acetone fromstep (f) using a catalyst containing at least one metal selected fromthe group consisting of niobium, iron, and manganese to form mesitylene,and (i) mixing the mesitylene with the isopentane from steps (c) and(d), whereby to form the biomass-derived high-octane fuel.
 22. Themethod of producing biomass derived high-octane fuel of claim 21,wherein the ethanol is converted to acetone in the presence of ironoxide catalysts.
 23. The method of producing biomass derived high-octanefuel of claim 21, wherein the ethanol is converted to acetone in thepresence of zinc oxide-calcium oxide catalysts and water vapor.
 24. Themethod of producing biomass derived high-octane fuel of claim 21,wherein the ethanol is converted to acetone by a gas phase catalysticreaction at elevated temperatures.
 25. The method of producing bio-massderived high-octane fuel of claim 21, wherein the trimerizing of acetonein step (h) is carried out in the gas phase by passing acetone incontact with a catalyst containing niobium oxide at elevatedtemperatures.
 26. The method of producing bio-mass derived high-octanefuel of claim 21, wherein the dimerization of acetone in step (g) iscarried out in a catalytic reaction to yield isopentane.
 27. The methodof producing bio-mass derived high-octane fuel of claim 21, wherein thedimerization of acetone in step (g) is carried out in a gas phasecatalytic reaction.
 28. The method of producing bio-mass derivedhigh-octane fuel of claim 21, wherein the trimerization of acetone instep (g) is carried out with a catalyst of niobium oxide on a base ofalumina washcoat on calcined aluminized stainless steel corrugated film.29. The method of producing biomass derived high-octane fuel of claim21, wherein the trimerization of acetone in step (g) is carried out witha catalyst of niobium oxide on a base of alumina beads.
 30. The methodof producing biomass derived high-octane fuel of claim 21, wherein thetrimerization of acetone in step (g) is carried out with a catalyst ofniobium oxide on silica gel.
 31. The method of producing biomass derivedhigh-octane fuel of claim 21, wherein the trimerization of acetone instep (g) is carried out with a catalyst of manganese nitrate on aluminabeads.
 32. The method of producing biomass derived high-octane fuel ofclaim 21, wherein the trimerization of acetone in step (g) is carriedout with a catalyst of manganese nitrate on silica gel.
 33. The methodof producing biomass derived high-octane fuel of claim 21, wherein thetrimerization of acetone in step (g) is carried out with a catalyst ofmanganese nitrate on a base of alumina washcoat on calcined aluminizedstainless steel corrugated film.
 34. The method of producing biomassderived high-octane fuel according to claim 1, wherein the microorganismis clostridium or variants thereof.
 35. The method of producing biomassderived high-octane fuel according to claim 16, wherein themicroorganism is clostridium or variants thereof.